1. Field of the Invention
This invention relates to the field of transmission kinematics, particularly to multiple speed gear arrangements.
2. Description of the Prior Art
Various techniques are used to produce multiple ratios of the speed of an input shaft and output shaft using gears and pinions, which are in continuous meshing engagement. For example, in a conventional manual transmission, pinions, comprising a cluster gear arrangement fixed to an input shaft, are driveably connected to an internal combustion engine, motor or other power source. The pinions are in continuous meshing engagement with corresponding gears journaled on the outer surface of an output shaft. In such gear arrangements a synchronizer or coupler is located between each adjacent pair of gears, the synchronizer having a hub that is continually fixed to the output shaft and a sleeve moved in opposite axial directions to produce a drive connection between each of the gears and the output shaft in response to movement by the vehicle operator of a gear selector mechanism.
Various automatic transmissions produce a speed ratio between the input shaft and output shaft through the use of meshing pinion-gear pairs. For example, U.S. Pat. No.6,033,332 describes a continuously variable transmission, within which two planetary gearsets operate as a power divider and a power combiner.
U.S. Pat. No. 6,086,501 describes a hydro-mechanical transmission having a mechanical power transmitting mechanism employing gears, the gearing including at least one planetary gear mechanism and an output shaft. The control of the gear mechanism includes a hydraulic pump and a hydraulic motor of the variable displacement type. A clutch is located between the output shaft of the motor and the output shaft of the gear mechanism.
U.S. Pat. No. 6,039,666 describes a hydraulic and mechanical transmission in which engine power is divided and transmitted to two output shafts, the first output shaft driving the hydraulic pump of a hydrostatic continuously variable transmission, the second output shaft driving a hydraulic motor through a gear mechanism.
In a mechanical power transmission providing multiple speed ratios between the input shaft and output shaft using a layshaft or countershaft arrangement, it is preferred that the axial space required for the transmission be minimized, the use of conventional synchronizers, clutches and brakes be eliminated, and the various speed ratios be produced through the cooperative action of a simple, low cost, dependable engagement mechanism, whose position and function are controlled with reference to engine operation parameters and vehicle speed.
In realizing these objects and advantages the transmission mechanism of this invention includes a first shaft having multiple pinions mutually spaced along the shaft and fixed to the shaft for rotation therewith; a second shaft substantially parallel to the first shaft, rotatably supporting mutiple gears thereon, each gear in meshing engagement with a pinion, having a bore extending along the second shaft and multiple radially directed passages spaced mutually along the second shaft, each passage located at the location of a gear; a control bar located in and extending along the bore, supported for movement relative to the second shaft, having an axially directed slot, and a guide rail having an axially directed track, an ascending ramp adjacent the track, and a descending ramp adjacent the ascending ramp; and locking bolts spaced mutually along the second shaft, each locking bolt located in a passage, extending through the axial slot, and retained in the guide rail.